btrfs: constify input buffer of btrfs_csum_data

The function does not modify the input buffer, also update a typecast in one caller. Signed-off-by: David Sterba <dsterba@suse.com>
mariux64 · Feb 28, 2017 · 9ed5736 · 9ed5736
1 parent da353f6
commit 9ed5736
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Showing 2 changed files with 3 additions and 3 deletions.
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
@@ -265,7 +265,7 @@ static struct extent_map *btree_get_extent(struct btrfs_inode *inode,
 	return em;
 }
 
-u32 btrfs_csum_data(char *data, u32 seed, size_t len)
+u32 btrfs_csum_data(const char *data, u32 seed, size_t len)
 {
 	return btrfs_crc32c(seed, data, len);
 }
@@ -3448,7 +3448,7 @@ static int write_dev_supers(struct btrfs_device *device,
 			btrfs_set_super_bytenr(sb, bytenr);
 
 			crc = ~(u32)0;
-			crc = btrfs_csum_data((char *)sb +
+			crc = btrfs_csum_data((const char *)sb +
 					      BTRFS_CSUM_SIZE, crc,
 					      BTRFS_SUPER_INFO_SIZE -
 					      BTRFS_CSUM_SIZE);

diff --git a/fs/btrfs/disk-io.h b/fs/btrfs/disk-io.h
@@ -116,7 +116,7 @@ void btrfs_mark_buffer_dirty(struct extent_buffer *buf);
 int btrfs_buffer_uptodate(struct extent_buffer *buf, u64 parent_transid,
 			  int atomic);
 int btrfs_read_buffer(struct extent_buffer *buf, u64 parent_transid);
-u32 btrfs_csum_data(char *data, u32 seed, size_t len);
+u32 btrfs_csum_data(const char *data, u32 seed, size_t len);
 void btrfs_csum_final(u32 crc, u8 *result);
 int btrfs_bio_wq_end_io(struct btrfs_fs_info *info, struct bio *bio,
 			enum btrfs_wq_endio_type metadata);